Latent Heat + Specific Heat Problem

AI Thread Summary
The discussion revolves around a physics problem involving the calculation of the amount of water that vaporizes when molten lead is poured into it. The participants analyze the equations for latent heat and specific heat, focusing on the correct application of these concepts to solve for the mass of water that boils. One contributor expresses confusion over differing numerical results, prompting a request for clarification on the calculations. The conversation highlights the importance of accurately plugging in values and simplifying equations to arrive at the correct answer. Ultimately, the thread emphasizes collaborative problem-solving in physics homework.
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Homework Statement



Suppose molten (liquid) lead, mass ml = 9.83 kg, is at its melting point. The lead is poured into water of mass mw = 585 g and initial temperature Tw = 16.2 C. Find mwb, the amount of the water that boils.
NOTE: Reaching the boiling point is not enough; the question asks for the amount of water that vaporizes as well.
ASSUME: no water evaporates; it only vaporizes at the boiling point.

Homework Equations


Constants: M.P Lead = 327 C, MP Water = 100 C
Latent Heat Lead = 33 kJ/kg
Latent Heat Q = mL
Specific Heat Eq'n: Q=mcΔT

The Attempt at a Solution


mL + mcΔT = mcΔT + mL
9.83 kg (33 kJ/kg) + 9.83 kg(0.130 kJ/kg)(327C - 100C) = 0.585(4.186)(100 -16.2) + m(2260 kJ/kg)
Solving for m, we get m = 0.215 kg.

Did I go wrong in my reasoning here? Many thanks in advance for your help!
 
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Your equation looks good to me. But I don't get the same numerical answer.
 
TSny said:
Your equation looks good to me. But I don't get the same numerical answer.

What do you get when you plug and chug in the values? I worked on the similar type of problem, and I got stuck on it from using that equation.
 
I get about 0.181 kg. What do you get for the numerical value of the left side of the equation? What do you get for the simplified form of the right side?
 
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